RESUMO
Objective @#To investigate the effect of miR-141-3p on LPS induced A549 cell injury by targeting high mobility group protein 1 (HMGB1) ．@*Methods @#A549 cells derived from type Ⅱ alveolar epithelial cells were taken as the study object，miR-141-3p mimics，mimics NC，HMGB1 gene overexpression plasmid (pcDNA3. 1-HMGB1) and empty Vector were transfected into A549 cells respectively or co-transfected，then 10 μg / ml LPS was used for 24 h．Cell proliferation activity was detected by cell counting kit-8 ( CCK-8) ．The activity of lactate dehydrogenase ( LDH) in the supernatant of cell culture was detected by colorimetry．The apoptosis level of each group was detec- ted by flow cytometry．The levels of interleukin (IL) -1 β , IL-6 and tumor necrosis factor α (TNF-α) were detected by enzyme-linked immunosorbent assay (Elisa) ．Dual luciferase reporter gene assay verified the targeted regulatory relationship between miR-141-3p and HMGB1 . @*Results @#After treatment with LPS ，the proliferative activity of A549 cells and the expression level of miR-141-3p decreased ( P ＜0. 05 ) ，the apoptosis rate increased ( P < 0. 05) ，the levels of IL-1 β , IL-6，TNF-α and the activity of LDH in supernatant increased (P＜0. 05) ．Overex- pression of miR-141-3p increased the proliferation activity of A549 cells treated with LPS (P ＜0. 05 ) ，and de- creased the apoptosis rate and the levels of IL-1 β , IL-6，TNF-α in cells and LDH activity in supernatant (P < 0. 05) ．However，overexpression of HMGB1 gene could reverse the ameliorative effect of miR-141-3p on LPS-in- duced A549 cell injury．Dual luciferase reporter gene experiment confirmed that HMGB1 was the downstream target gene of miR-141-3p．@*Conclusion @# miR-141-3p can inhibit LPS-induced apoptosis，reduce the expression level of inflammatory factors，and improve the damage of A549 cells，which may be related to the targeted regulation of HMGB1 expression.
RESUMO
Objective To investigate the effect and mechanism of miR-141-3p on pulmonary fibrosis in rats with acute respiratory distress syndrome(ARDS).Methods Rats were divided into the control group,the model group,the agomir negative control group and the miR-141-3p agomir group according to random number table,with 10 rats in each group.In addition to the control group,the ARDS rat model was established by lipopolysaccharide(LPS)infusion.Rat alveolar typeⅡepithelial cells RLE-6TN cells were divided into the NC group,the LPS group,the miR-NC group,the miR-141-3p mimics group,the miR-141-3p mimics+pcDNA group and the miR-141-3p mimics+NRF2 and Kelch-like ring associated protein 1(Keap1)group.LPS cell model was established in all groups except the NC group.The mRNA expression levels of miR-141-3p and Keap1 in lung tissue and cells were detected by qPCR.Western blot assay was used to analyze lung tissue and cell epithelial cadherin(E-cadherin),neural cadherin(N-cadherin),microtubule associated protein light chain 3B(LC3B),autophagy associated gene Beclin-1,α-smooth muscle actin(α-SMA),type I collagen(Col-Ⅰ),Keap1 and nuclear factors E2 related factor 2(NRF2)and heme oxygenase 1(HO-1).HE staining and Masson staining were used to observe pathological changes of lung tissue and to estimate the area of lung tissue injury and pulmonary fibrosis.Hydroxyproline(Hyp)in lung tissue was detected by the kit.Levels of inflammatory factor interleukin-1β,tumor necrosis factor(TNF-α)and oxidative stress index malondialdehyde(MDA)and superoxide dismutase(SOD)were detected by ELISA.Dual luciferase reporting experiment was used to verify the targeting relationship between miR-141-3p and Keap1.Results The expression of miR-141-3p was down-regulated and the expression of Keap1 was up-regulated in lung tissue and cells(P＜0.05).Overexpression of miR-141-3p can reduce the degree of pathological damage and fibrosis of lung tissue in rats,Hyp content,and up-regulate expression levels of SOD,E-cadherin,LC3B,Beclin-1,NRF2 and HO-1 in lung tissue and cells,and down-regulate the expression levels of IL-1β,TNF-α,MDA,N-cadherin,α-SMA,Col-I and Keap1(P＜0.05).Overexpression of Keap1 was able to reverse the improvement effect of overexpression of miR-141-3p on alveolar epithelial cell damage in ARDS rats(P＜0.05).Double Luciferase reporter gene experiment confirmed that miR-141-3p and Keap1 may have a targeted regulatory relationship.Conclusion Overexpression of miR-141-3p may activate the Keap1-NRF2/ARE signaling pathway,activate autophagy,inhibit inflammatory response,oxidative stress,and EMT progression,and improve pulmonary fibrosis in ARDS rats.